Did Don Draper create the famous Coca-Cola "Hilltop" commercial in Sunday's finale of "Mad Men"? In an interview Wednesday night at the New York Public Library, series creator and episode writer Matthew Weiner gave a definite . . . maybe.

"I am not that clear," he told the interviewer, novelist A.M. Homes, of both his life and his writing style, "I have always been able to live with ambiguities. . . . People are like, 'Well, which is it?' . . . Well, why does it have to be one or the other?"

In the episode's final moments, ad-agency creative director Draper, played by Jon Hamm, has found himself at an Esalen-like spiritual retreat in California in late 1970. As he and a small group of people are led in a meditative chant, a bell rings and a slow smile spreads across the troubled Draper's face. He appears, perhaps, to be finally at peace with himself. Then the image cuts to the iconic 1971 Coke commercial. Did Draper remain retired, with the commercial simply symbolic of how the ad industry co-opts modern culture? Or did the smile represent his great idea for an ad?

Weiner reflected that, "I am not for ambiguity for ambiguity's sake. But it was nice to sort of have your cake and eat it, too, in terms of 'What is advertising? Who is Don? And what is that thing?' "

As to the possibility of Draper having created the legendary commercial, Weiner said he liked "the idea that some enlightened state and not just co-option might have created something that is very pure."

Created by Bill Backer for McCann Erickson, the real-life ad agency for which the fictional Draper works, "Hilltop" is considered an advertising classic, with its original film archived at the Library of Congress.